VERTICAL EYE MOVEMENT-RELATED SECONDARY VESTIBULAR NEURONS ASCENDING IN MEDIAL LONGITUDINAL FASCICULUS IN CAT .1. FIRING PROPERTIES AND PROJECTION PATHWAYS
VERTICAL EYE MOVEMENT-RELATED SECONDARY VESTIBULAR NEURONS ASCENDING IN MEDIAL LONGITUDINAL FASCICULUS IN CAT .1. FIRING PROPERTIES AND PROJECTION PATHWAYS
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DOI：
10.1152/jn.1990.63.4.902
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发表时间：
1990-04-01
影响因子：
2.5
通讯作者：
YOSHIDA, K
中科院分区：
文献类型：
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作者：
IWAMOTO, Y;KITAMA, T;YOSHIDA, K
1. 研究了警觉性猫参与前庭垂直通路的前庭次级核神经元的放电特征和投射模式。前庭神经电刺激后单突触激活的轴突在滑车核附近的内侧纵束（MLF）进行单单元记录。在总共253个确定的次级神经元中，225个与垂直眼运动有关；其中189人在眼球向下运动时增加了放电速率，36人在眼球向上运动时增加了放电速率。当头部静止时，其余28个轴突的活动与眼球运动无关。2. 几乎所有向下定向的次级神经元都表现出紧张性活动，这主要与注视时眼睛位置的稳定有关（DPV神经元）。射速与眼垂直位置关系的斜率范围为1.2 ~ 9.1（尖峰/秒）/度，平均值为3.2（尖峰/秒）/度。通过计算穗间间隔的变异系数（CV），定量分析了发射规律。通过对种群单位CV的比较，DPV神经元可以分为规则神经元和不规则神经元。与不规则神经元相比，规则神经元有更高的放电速率和更高的速率-位置关系相关系数的趋势。3. 在光线下俯仰旋转时，所有被测的DPV神经元都随着头部向上旋转而增加放电速率。反应的相位和振幅都表明，DPV神经元不仅与眼睛位置有关，而且与头部速度有关，这表明它们接受了来自后半规管的单突触输入。在0.5 Hz下测量了相对于头部速度的响应增益和相位滞后。增益范围为1.1 ~ 5.1（尖峰/秒）/（度/秒），相位滞后范围为18.3 ~ 62.4度。与规则DPV神经元相比，不规则DPV神经元具有更大的增益和更小的相位滞后。4. 测定147个DPV轴突的上升和下降投影通路。通过对侧或同侧前庭神经的单突触激活显示，其中69个在对侧MLF（交叉的dpv轴突）上升，78个在同侧MLF（未交叉的dpv轴突）上升。尾侧MLF在obx水平上的刺激引起了大约70%（49/69）交叉dpv轴突的下行侧支的反向激活所引起的直接反应。（摘要删节为400字）
1. The firing characteristics and projection patterns of secondary vestibular nucleus neurons involved in the vertical vestibuloocular pathways were investigated in alert cats. Single-unit recordings were made in the medial longitudinal fasciculus (MLF) near the trochlear nucleus from axons that were monosynaptically activated after electrical stimulation of the vestibular nerve. In a total of 253 identified secondary neurons, 225 discharged in relation to vertical eye movements; 189 of these increased their firing rate for downward eye movements and 36 for upward movements. The activity of the remaining 28 axons was not related to eye movements when the head was still. 2. Virtually all of the secondary neurons with downward on-direction displayed tonic activity that was primarily related to steady eye position during fixation (DPV neurons). The slope of the relationship between firing rate and vertical eye position ranged from 1.2 to 9.1 (spikes/s)/deg with a mean of 3.2 (spikes/s)/deg. The regularity of firing was quantified by calculating the coefficient of variation (CV) of interspike intervals. A comparison of the CV in the population units indicated that DPV neurons could be classified as either regular or irregular neurons. There was a tendency for regular neurons to have higher firing rates and higher correlation coefficients for the rate-position relationships than irregular neurons. 3. During pitch rotation in the light, all the DPV neurons tested increased their firing rate with upward head rotation. Both the phase and the amplitude of the response indicated that DPV neurons discharged not only in relation to eye position but also in relation to head velocity, suggesting that they received monosynaptic input from the posterior semicircular canal. The gain and phase lag of the response relative to head velocity were measured at 0.5 Hz. The range of the gain was 1.1-5.1 (spikes/s)/(deg/s), and that of the phase lag was 18.3-62.4 degrees. There was a tendency for irregular DPV neurons to have a larger gain and smaller phase lag than regular DPV neurons. 4. Ascending and descending projection pathways were determined for 147 DPV axons. Of these, 69 ascended in the contralateral MLF with respect to their soma (crossed-DPV axons), and 78 in the ipsilateral MLF (uncrossed-DPV axons), as revealed by their monosynaptic activation from the contralateral or ipsilateral vestibular nerve. Stimulation of the caudal MLF at the level of the obex evoked direct responses caused by antidromic activation of descending collaterals in approximately 70% (49/69) of the crossed-DPV axons.(ABSTRACT TRUNCATED AT 400 WORDS)